This project will focus on studying the inheritance patterns of well-defined vocalizations in selected primates, particularly the squirrel monkey. Crossbreeding of closely related species or subspecies with distinctly different vocalizations will provide the opportunity for analysis of the parental contributions of hybrid vocal traits. Collaboration with other units expert in cellular genetic methods is expected to provide information regarding the transmission of genetic material to hybrid offspring as well as the genetic distances between members of the parental populations. Additional primate species will be examined for presence of distinctive vocal traits and interspecific hybridization, to evaluate their usefulness in this area of genetic research.